What Does "Fay Sor Loh" Mean?

My boyfriend has always had a thing for chinese girls, and all preovious girlfirends... chinese.. im not. When a certain old "friend" of him rings, she keeps saying "Fay Sor Loh" then laughing lots. But he won't tell me what it means. Now its wrote all over his facebook.

Long story short,. I would love to know what this means!

He has a cantonese translations book (presumably for getting in with all those chinese ex's, )and they (the chinese girl who keeps writing " Fay Sor Loh") lived in Ireland if this helps?